From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id B23B438515F6; Wed, 14 Sep 2022 16:09:53 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B23B438515F6
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1663171793;
	bh=+q1YJO1p/rsTcyc3FP7g/rCSGXuNsXE7PGIquDGudaA=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=X6hw3UAJIP377VzYlsamFmCDAGNwy6njg/0WX2EJ86EPrgiKbY1WGaPy+dKP/k3FE
	 MdjAKWQWv3KT5JymOsIn8WcJZLXpsZIJ2VQ01Z93d2f5yuGNpg4kfuaw+KMAjQZeQn
	 o39Xuq3cxzWqDsmEOukbBQ99l2IEkGFCPYjmJQlg=
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/106939] Linker-defined symbols are stained due to 'array
 subscript is partly outside array bounds' warning
Date: Wed, 14 Sep 2022 16:09:53 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c
X-Bugzilla-Version: 12.2.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: pinskia at gcc dot gnu.org
X-Bugzilla-Status: RESOLVED
X-Bugzilla-Resolution: INVALID
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-106939-4-eSvZPQFcMF@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-106939-4@http.gcc.gnu.org/bugzilla/>
References: <bug-106939-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106939

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Arseny Vakhrushev from comment #4)
> Thanks a lot, Andrew! Totally my bad. Well, comparison seems to work too:
>=20
> extern char _src[], _dst[], _end[]; // Defined by the linker
> int main(void) {
>     char *src =3D &_src[0];
>     char *dst =3D &_dst[0];
>     char *end =3D &_end[0];
>     while (src < end) *dst++ =3D *src++;
>     return 0;
> }
>=20
> Are the asm("" : "+r" (p)) statements strictly needed?

The inline-asm is needed because in C it is undefined to compare pointers t=
hat
are from different arrays. Basically it is a way to hide it from the compil=
er.=